Combustion temperatures encountered within cylinders of an internal combustion engine can lead to overheating of the cylinders as well as pistons arranged within the cylinders. A lubrication system may be used to cool the pistons by squirting oil towards the pistons.
For example, pistons may be cooled via piston cooling jets wherein oil is sprayed at an underside of the piston. An example piston cooling assembly is described by Chimonides et al. in U.S. Pat. No. 6,298,810 wherein an oil nozzle is located on an engine block to supply oil to the underside of the piston. The inventors herein have recognized potential issues with piston cooling via piston cooling jets. For example, piston cooling jets may be operated in a continuous manner, such that cooling oil is constantly sprayed from the oil nozzle. As such, a larger proportion of the oil may be sprayed without cooling the piston due to the reciprocating motion of the piston. For example, a significant portion of the cooling oil may not reach the piston when the piston is at top dead center position in the cylinder. Thus, larger amounts of oil may be sprayed towards the piston to effectively cool the piston. Accordingly, oil pumps may be sized to pump larger volumes of oil towards the piston. Herein, larger sized oil pumps can increase power consumption and therefore, reduce engine efficiency.
The inventors herein have recognized the above issues and developed an approach to at least partly address the above issues. In one example approach, a method may comprise delivering oil to an underside of a piston arranged within a cylinder of an engine via an internal passage in a connecting rod of the piston, the internal passage fluidically coupled at a first end to an external nozzle, the external nozzle located below a wrist pin bore of the connecting rod. In this way, the piston may be cooled continuously.
In another example, a system may comprise an engine including a cylinder, a piston reciprocating within the cylinder, a connecting rod coupling the piston to a crankshaft, a first end of the connecting rod including a first bore coupled to a crank pin of the crankshaft via a connecting rod bearing, a second end of the connecting rod including a second bore coupled to the piston via a wrist pin, a beam of the connecting rod spanning a distance from the first end of the connecting rod to the second end of the connecting rod, the beam comprising a web section, a first flange, and a second flange, wherein each of the first flange and the second flange are hollow, an internal groove formed on a portion of an inside circumference of the first bore, the internal groove adapted to receive oil from an oil hole on the connecting rod bearing, a first passage within the first flange fluidically coupling the internal groove with a first nozzle, the first nozzle arranged at the second end of the connecting rod, and a second passage within the second flange fluidically coupling the internal groove with a second nozzle, the second nozzle arranged at the second end of the connecting rod away from the first nozzle.
In this way, a piston of a cylinder in an internal combustion engine may be cooled effectively with less waste of pressurized oil. By delivering oil to the underside of the piston in a continuous manner, the piston may be cooled throughout its travel within the cylinder. As such, a likelihood of piston degradation may be diminished. Further, since the piston is cooled via oil received from the connecting rod bearing, the oil pump may be downsized enabling a technical effect of a reduction in power consumption. Overall, engine operation may be enhanced and engine performance may be improved.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. Additionally, the above issues have been recognized by the inventors herein, and are not admitted to be known.